Motor drive for a camper jack

ABSTRACT

A motor drive for camper jacks or screw jacks that rapidly operates the screw jack between a retracted position and an extended no load position. A manual operator then operates the screw jack between the extended no load position and an extended loaded position. The motor drive and manual operator share a right angle gear mechanism.

BACKGROUND OF THE INVENTION

This invention relates generally to a screw jack for recreationalvehicles and more particularly to motor operator for a screw jack forrecreational vehicles.

Recreation vehicles, such as motor homes, travel trailers, campers,etc., are preferably leveled and stabilized when parked for convenienceand comfort. Stabilizing the RV reduces vibration and bouncing uponmovement inside. Prior art screwjacks can be slow to operate between aretracted or travel position and an extended position where the screwjack can be loaded to level and stabilize the recreational vehicle.

The foregoing illustrates limitations known to exist in present screwjacks. Thus, it is apparent that it would be advantageous to provide analternative directed to overcoming one or more of the limitations setforth above. Accordingly, a suitable alternative is provided includingfeatures more fully disclosed hereinafter.

SUMMARY OF THE INVENTION

In one aspect of the present invention, this is accomplished byproviding a drive for a screw jack comprising: a motor having an axis ofrotation; and a gear mechanism having a shaft therein, an end of theshaft having a hex head thereon, an opposite end of the shaft having ahex socket therein, the hex socket having a complementary shape and sizeto the hex head.

In a second aspect of the present invention, this is accomplished byproviding a drive for a screwjack, the screwjack having a drive screwrotating about an axis, the drive comprising: a motor having an axis ofrotation; and a right angle gear mechanism having: a worm gear attachedto the motor, the worm gear rotating about the motor axis of rotation; aspur gear mounted on a shaft, the spur gear engaging the worm gear, theshaft having an axis extending at a right angle to the motor axis ofrotation, wherein the spur gear shaft is coaxial with the drive screwaxis of rotation.

In a further aspect of the present invention, this is accomplished byproviding in combination: a screw jack including an elongated drivescrew rotating about an axis; and a drive apparatus operating thescrewjack, the drive apparatus comprising: a motor having an axis ofrotation; and a right angle gear mechanism having: a worm gear attachedto the motor, the worm gear rotating about the motor axis of rotation; aspur gear mounted on a shaft, the spur gear engaging the worm gear, theelongated drive screw axis extending at a right angle to the motor axisof rotation.

In a further aspect of the present invention, this is accomplished byproviding a screw jack comprising: means for rapid translation of thescrew jack between a retracted position and an extended no loadposition, the means for rapid translation of the screw jack comprisingan electric motor; and means for further translation of the screw jackbetween the extended no load position and an extended loaded position,the means for further translation of the screw jack comprising a manualoperator.

The foregoing and other aspects will become apparent from the followingdetailed description of the invention when considered in conjunctionwith the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a perspective view of a drive for use with a screw jackaccording to the present invention;

FIG. 2 is second perspective view of the drive shown in FIG. 1;

FIG. 3 is a perspective view of the drive shown in FIG. 1 and a screwdrive stabilizing jack;

FIG. 4 is a perspective view of the stabilizing jack shown in FIG. 3;

FIG. 5 is a perspective view of the drive shown in FIG. 1 and a screwdrive leveling scissors jack;

FIG. 6 is a perspective view of the leveling scissors jack shown in FIG.3;

FIG. 7 is a plan view of the drive shown in FIG. 1, with a portion ofthe gear housing removed; and

FIG. 8 is a plan view of the drive gear mechanism shown in FIG. 1, witha portion of the gear housing removed.

DETAILED DESCRIPTION

FIG. 1 illustrates a jack power drive 10 for power operation of a screwjack or camper jack such as the stabilizing jack 40 shown in FIG. 4 orthe leveling scissors jack 50 shown in FIG. 6. Drive 10 comprises amotor 20 connected to a gear assembly 22. Preferably, gear assembly 22is a right angle gear assembly. The motor 20 includes a armature shaft(not shown) that extends into the right angle gear assembly 22. A wormgear 28 (see FIG. 7) fits on the end of the motor armature shaft.

As shown in FIGS. 7 and 8, the right angle gear assembly 22 includes ahousing 25 that is attached to the motor 20. A spur gear shaft (notnumbered) is rotatably supported within the housing 25. The spur gearshaft has a centerline 23 that extends at a right angle to a centerline21 of the motor. A spur gear 27 is mounted on the spur gear shaft andengages the motor worm gear 28. One end of the spur gear shaftterminates in a hex head 24 and the other end of the spur gear shaftterminates in a hex socket 26. Hex socket 26 has a complementary shapeand size to hex head 24.

Drive 10 is intended to work with many types of screw jacks, i.e., jacksthat use an elongated threaded drive rod. One type of screw jack 40, astabilizing jack, is shown in FIGS. 3 and 4. Stabilizing jack 40 isoperated by rotating an elongated threaded screw (not shown) to extend aleg 48. The elongated threaded screw terminates in a hex head 42. Thejack hex head 42 has a shape and size that is complementary to drive hexsocket 26. Drive 10 is attached to stabilizing jack 40 by fittingstabilizing jack hex head 42 into drive hex socket 26. Brackets 44 areattached to drive 10 and stabilizing jack 40. Screws fit throughmounting holes 45 in bracket 44 and mounting holes 47 in stabilizingjack 40 to attached the drive 10 to the stabilizing jack 40 and to therecreational vehicle.

In operation, motor 20 is rotated in a first direction, which via theright angle gear assembly 22, rotates hex head 42 and the elongatedthreaded screw in a first direction causing leg 48 to extend from arecessed position (not shown) to an extended position. Motor 20 isoperated until leg 48 contacts the ground and begins to pick up load. Ina preferred embodiment, motor 20 is not large enough to continue tooperate jack 40 once load is picked up by jack 40. To continue tooperate jack 40 to pick up load and stabilize the recreational vehicle,drive hex head 24 is manually operated to continue to rotate the rightangle gear shaft and the elongated jack threaded drive shaft to whichdrive 10 is attached by drive hex socket 26. Any appropriate operator,such as a socket wrench, a box wrench, an adjustable wrench, crankhandle, etc., can be used to engage drive hex head 24 and to manuallyoperate drive 10.

In a preferred embodiment, the teeth on spur gear 27 extend at an angle29 to the spur gear center line 23. Angle 29 is large enough to allowback driving of motor 20. This facilitates the manual operation of thedrive 10 without impeding the operation of motor 20.

To lower the recreational vehicle and retract jack 40 to the recessedposition, the above operation is reversed. Drive hex head 24 is manuallyoperated to lower the recreation vehicle until the load on the jack 40is reduced. Then, motor 20 is operated to fully retract jack 40 to therecessed position.

One second type of screw jack 50, a leveling scissors jack, is shown inFIGS. 5 and 6. Leveling scissors jack 50 is operated by rotating anelongated threaded screw 53 to raise a lift platform 51. The elongatedthreaded screw 53 terminates in a hex head 52. The jack hex head 52 hasa shape and size that is complementary to drive hex socket 26. Drive 10is attached to leveling scissors jack 50 by fitting scissors jack hexhead 52 into drive hex socket 26. Brackets 54 are attached to drive 10and leveling scissors jack 50. The leveling scissors jack 50 is attachedto the recreational vehicle by bolting the lift platform 51 to therecreational vehicle. Apertures 57 in mounting brackets 54 fit about theends 56 of a scissors jack trunnion and the mounting brackets 54 aresecured to the right angle gear housing 25.

In operation, motor 20 is rotated in a first direction, which via theright angle gear assembly 22, rotates hex head 52 and the elongatedthreaded screw 53 in a first direction causing the leveling scissorsjack 50 to extend from a retracted position (not shown) to an extendedposition. Motor 20 is operated until foot 58 contacts the ground and thejack 50 begins to pick up load. In a preferred embodiment, motor 20 isnot large enough to continue to operate jack 50 once load is picked upby jack 50. To continue to operate jack 50 to pick up load and level therecreational vehicle, drive hex head 24 is manually operated to continueto rotate the right angle gear shaft and the elongated jack threadeddrive shaft to which drive 10 is attached by drive hex socket 26. Anyappropriate operator, such as a socket wrench, a box wrench, anadjustable wrench, crank handle, etc. can be used to engage drive hexhead 24 and to manually operate drive 10.

To lower the recreational vehicle and retract jack 50 to the retractedposition, the above operation is reversed. Drive hex head 24 is manuallyoperated to lower the recreation vehicle until the load on the jack 50is reduced. Then, motor 20 is operated to fully retract jack 50 to theretracted or recessed position.

In a further aspect, the present invention comprises a means for rapidlytranslating the jack 40, 50 between the retracted position to anextended no load position and a means for further translating the jack40, 50 to an extended loaded position. The means for rapidly translatingthe jack to the extended no load position comprises the motor 20, rightangle gear mechanism 22 and the jack threaded screw 53. The means forfurther translating the jack to the extended loaded position comprisesthe right angle gear assembly 22, the jack threaded screw 53 and themanual operator attached to the drive hex head 24.

1. A drive for a screw jack comprising: a motor having an axis ofrotation; and a gear mechanism having a shaft therein, an end of theshaft having a hex head thereon, an opposite end of the shaft having ahex socket therein, the hex socket having a complementary shape and sizeto the hex head.
 2. The drive according to claim 1, wherein the gearmechanism is a right angle gear mechanism having: a worm gear attachedto the motor, the worm gear rotating about the motor axis of rotation;and a spur gear mounted on a shaft, the spur gear engaging the wormgear, the shaft having an axis extending at a right angle to the motoraxis of rotation.
 3. The drive according to claim 1, wherein the teethon the spur gear are at an angle large enough to permit back driving ofthe motor.
 4. A drive for a screw jack, the screw jack having a drivescrew rotating about an axis, the drive comprising: a motor having anaxis of rotation; and a right angle gear mechanism having: a worm gearattached to the motor, the worm gear rotating about the motor axis ofrotation; a spur gear mounted on a shaft, the spur gear engaging theworm gear, the shaft having an axis extending at a right angle to themotor axis of rotation, wherein the spur gear shaft is coaxial with thedrive screw axis of rotation.
 5. The drive according to claim 4, whereinan end of the shaft has a hex head thereon, an opposite end of the shafthas a hex socket therein, the hex socket having a complementary shapeand size to the hex head.
 6. The drive according to claim 5, wherein theteeth on the spur gear are at an angle large enough to permit backdriving of the motor.
 7. In combination: a screwjack including anelongated drive screw rotating about an axis, the drive screw having ahex head on one end thereof; and a drive apparatus operating the screwjack, the drive apparatus comprising: a motor having an axis ofrotation; and a right angle gear mechanism having: a worm gear attachedto the motor, the worm gear rotating about the motor axis of rotation;and a spur gear mounted on a shaft, the spur gear engaging the wormgear, the elongated drive screw axis extending at a right angle to themotor axis of rotation.
 8. The combination according to claim 7, whereinthe spur gear shaft has a hex socket on an end thereof, the hex socketengaging the drive screw hex head.
 9. The combination according to claim8, wherein the spur gear shaft has a hex head on a second end thereof,the spur gear hex head having the same shape and size as the drive screwhex head.
 10. The combination according to claim 7, wherein the screwjack comprises a leveling scissors jack.
 11. The combination accordingto claim 7, wherein the screw jack comprises a stabilizing jack.
 12. Ascrew jack comprising: means for rapid translation of the screwjackbetween a retracted position and an extended no load position, the meansfor rapid translation of the screw jack comprising an electric motor;and means for further translation of the screw jack between the extendedno load position and an extended loaded position, the means for furthertranslation of the screw jack comprising a manual operator.
 13. Thescrew jack according to claim 12, wherein the screw jack comprises aleveling scissors jack.
 14. The screw jack according to claim 12,wherein the screw jack comprises a stabilizing jack.
 15. The screw jackaccording to claim 12, wherein the means for rapid translation of thescrew jack and the means for further translation comprises a sharedright angle gear mechanism.